Patent GB-1444762-A (GB)
Title: Solid state electronic wristwatch
IPC: G04G9/10
Filed: 1973-09-04
Abstract: 1444762 Electronic watches TIME COMPUTER Inc 4 Sept 1973 [1 Feb 1973] 41578/73 Heading G3T An electronic wrist watch comprises a time computing circuit coupled to a frequency standard and a calendar circuit coupled to the time computer, a common de-coder coupling both the time computing circuit and the calendar circuit to an electro-optical display, - e.g. 7 bar-segment type of light-emitting diodes or alternatively liquid or ferro-electric crystal, incandescent bulbs or electroluminescent elements. The electrical components are mounted in a one piece frame, 580, Fig. 16, of insulating material e.g. nylon. General. The time is displayed only on demand and only one digit of the display being in an energized state at a time, under control of a strobe circuit, persistence of vision giving the appearance of simultaneous illumination of all digits. On pressing and then releasing a time demand button the hours and mins will be displayed on four digit display devices for 1 secs only as determined by a time constant circuit. Continued pressing of the time demand button will result in the display of seconds on the minutes (or hours) digit positions. On pressing a date demand button the day and month will be displayed on the said four display devices used for mins and hours. (For use in Europe the month display may be optionally prevented). Also the number of days in the month - 28, 29, 30, 31 is automatically taken into account. A.M./P.M. is indicated by illumination of colon dots between the mins and hours displays. The intensity of illumination is automatically controlled by a photosensitive detector. The display is viewed through a red filter. The demand push buttons for time and date carry permanent magnets which co-operate with reed switches. Setting is effected at a "fast" rate of 2 hours/sec or at a "slow" rate of 2 minutes/ sec. by manually applying a permanent magnet to special indents in the watch casing Fig. 28 (not shown) whereby to operate respective reed switches. The watch strap is provided with storage means for the magnet. The watch case is non- magnetic. The time computer circuit 70 and the calendar circuit 141 are formed in separate L.S. integrated circuit chips as illustrated in Figs. 10, 11 (not shown); alternatively they may be combined in one chip. The time computer circuit is detailed in Figs. 8A, 8B, 8C and the calendar circuit 141 in Figs. 9A, 9B (not shown). Time Computer Module. As shown Figs. 8A, 8B, 8C, seconds, tens of secs, mins, tens of mins, hours are stored in registers 172, 174, 176, 178, 180 respectively. The units stored in each are applied via respective transmission gates 182, 190, 192, 194, 198 and via four input gates 184 to a de-coder 186. This converts BCD signals from the registers into drive signals for the display and which are applied via buffer amplifiers 188 to the appropriate segments a to g of the display. A strobing circuit 216, Fig. 8c, enables the transmission gates 182 &c. by its outputs A to F to control which time signals are to be displayed, while its outputs S 1  - S 4  are applied to strobe transistors (82) (84) (86) (88) Fig. 7 (not shown) for energizing appropriate display digits while the outputs a to g of the de-coder driver 186 control driver transistors (112), (114), (116), (118), (120), (122), (124), Fig. 7 (not shown) whereby to provide power to those display segments which are to be activated in accordance with the BCD input number. The pulse width of the energizing signals is varied to vary the intensity. The calendar circuit provides BCD signals to the computer circuit 70 at terminals Qi - Q 4  Fig. 8A, which signals are selectively applied via transmission gates 285 to the common de-coder 186 for displaying day, month, and AM/PM. information. Structural arrangements of the watch casing, battery and components mounting are described with reference to Figs. 13 to 34 (not shown).